RAID0 is commonly used by gamers and it is basically using 2 or more disks as one in order to achieve higher read/write speeds.

And I laugh at most gamers who did this, after seeing time and time again that it ends up being slower. Why? Well the benchmarks aren't trying to do other things with the CPU during the benchmark, so it seems fine. But toss in a game loading, and all of a sudden their der cheep IDE RAID card and it's software RAID implemented via drivers chokes their system.

Raid 5, well, get a hardware controller for sure. And not just because of the dynamic disk mess, but because having to do Raid 5 calculations in software sucks. Newer Smart Array controllers (Generation 4-6) actually have IBM PowerPC processors to do dedicated Raid 5/6 calculations.